Inhalation devices are well-known alternatives to parenteral administration of medication and are available in a variety of inhaler styles. Methods of administration for inhaled medications include metered-dose inhalers, nasal spray devices, and nebulizers. These medications provide a rapid onset of action and relief of symptoms by applying medication directly to the lung tissue or nasal mucosa.
Inhalers are an essential component in the management of asthma, allergic rhinitis and other common medical ailments. More recent uses include pain management, diabetes insipidus, and osteoporosis.
Oral metered-dose inhalers, which administer medication directly to the lung tissue, consist of a pressurized metal canister filled with medication. The pressurized canister is inserted into a hollow plastic outer-body with an opening on one end that becomes a mouthpiece for drug administration. The patient administers a dose by pressing down on the metal canister and activating the device.
Nasal inhalers have two basic designs. The first design, a nasal metered-dose inhaler, is similar to the oral metered-dose inhalers with a pressurized aerosol canister placed inside a plastic outer body. The second design, a nasal spray, consists of a glass or plastic container fitted with a pump-style administration device. The patient pushes the bottom of the container to administer the dose.
The third type of administration device, a nebulizer, uses a machine to provide a fine mist of drug to the patient. The active drug is mixed with saline or other diluent and is administered through tubing connected to the nebulizer.
The number of inhaler users in the United States is large and growing. According to statistics from the National Health Interview Survey, 88,226,000 people reported chronic respiratory or sinus conditions in 1992. These conditions are often treated with inhaler-type medications. The growth in the number of allergy and asthma sufferers is expected to continue. Death rates of asthma patients in the United States increased from 0.8 per 100,000 general population in 1977 to 2.0 per 100,000 in 1991. Estimated total hospital and drug store sales on beta-adrenergic metered-dose inhalers increased from 10.3 puffs per person in 1976 to 31.0 in 1991; those for inhaled corticosteroids from 0.44 puffs per person in 1976 to 5.44 in 1991. Sales of administration-related devices have also increased.
Patient compliance, motivation, and understanding of these diseases and treatments are essential factors for successful control of asthma and allergic rhinitis. Patients must administer their medications at the proper schedule and dosage without direct supervision of doctors or other health care personnel. Patients who follow their regimens correctly can control symptoms and reduce asthma and allergy relapses, as well as trips to the physician's office or hospital. Studies evaluating new asthma medications indicate that patients often under-use, over-use and/or inappropriately use their medications. Because of the consequences of non-compliance, new products to improve patient compliance and utilization are well-received by patients and health care providers alike.
A majority of today's metered-dose inhalers do not have a way to track the number of doses released from the canister and cannot compute the number of doses remaining in the canister. Once the inhaler is dispensed from the pharmacy, the user is responsible for remembering the number of doses remaining in the container. Various methods to determine the number of doses remaining in the container have been utilized over the years. Some users drop the metal canister into a glass of water, the container sinks when it contains medication or floats when almost empty. Other users shake the container to listen for medication in the canister while still others utilize a paper calendar or table and cross-off the number of doses as they are administered.
These methods are inaccurate so users often find themselves with an empty inhaler canister. Asthma patients who unexpectedly find themselves without medication during times of stress or acute asthma attacks often experience serious medical complications and even death. Allergic rhinitis patients must take regular doses of corticosteroids to avoid severe allergy symptoms that occur if therapy is stopped abruptly. Because oral and nasal inhalers are prescription drugs that require a physician's authorization for refills, emergency refills are difficult to obtain when the patient is away from home or uses a mail-order pharmacy or when the patient's regular pharmacy is closed. Because the inhaler often does not have a prescription label affixed to the inhaler body, the patient may be unaware that the prescription has no more refills remaining. When the inhaler prescription can no longer be refilled, the pharmacist must contact the physician for authorization of additional refills, which inconveniences the patient, pharmacist and physician. When symptoms are severe or the physician is unavailable, the patient must seek medical attention from a hospital or clinic.
If patients were aware of the number of doses they have used and the approximate number remaining in the canister, they could anticipate refills early so the complications, inconveniences and added costs of an untreated asthma attack or allergic reaction can be avoided. A counting mechanism designed to track the number of doses administered from the inhaler will provide a way to monitor usage and avoid running out of medication.
Prior art devices have been provided which count doses of dispensed medication, however, the counting mechanisms typically require activation of the inhaler to advance the counting mechanism, thereby providing "automatic" counting. Designs incorporating the counting mechanisms into the plastic outer body of the inhaler add substantial cost to the inhaler. These designs also require customization of the counting mechanism for each specific brand and design of inhaler. The more complex devices would be extremely costly and require training for the patient and health care professional to use the inhaler correctly. One device requires programming by a pharmacist or physician with data collected by the device stored until the physician or pharmacist interprets the information. The patient utilizing such a device does not have access to the information collected until the next office visit or prescription refill.
Another difficulty with inhaler use is design of the inhaler canister and containers. Inhalers are expensive and important items that must be protected from dirt, dust, water, sunlight, and damage. One inhaler may be carried for weeks or months until it is replaced. However, allergy and asthma attacks can happen at any time, so inhalers made of plastic, metal or glass are frequently carried unprotected in purses, pockets, book bags, briefcases, or such items for immediate use. Consequently, they may become separated, broken, clogged or accidentally activated. Another difficulty is that although inhalers provide easy access to the patient, they are not particularly child-resistant. A small child can easily press on the container and spray active drug into his or her eyes, nose or mouth, in addition to wasting expensive medication. None of the prior art devices address the issue of protection of the inhaler from the above hazards.
Finally, prescription labels are difficult to place on inhaler canisters and containers. The container shapes are irregular and small in size. The labels are often too large for the canister or container so the pharmacist usually places the label on the outer cardboard shipping box. The box is usually discarded by the patient so vital labeling information necessary for prescription refills, school use and emergency situations is lost.
Currently, a carrying case designed specifically for oral and nasal inhalers is not available. A case with a counting mechanism would be very helpful to the user. Since prior art devices focus on the plastic outer body of the inhaler, each type of inhaler must be redesigned to accommodate the counting mechanism. If the user breaks, soils or loses the inhaler outer body, another expensive plastic outer body must be purchased. At present, none of the prior art devices have found their way into mainstream inhaler usage, possibly because of manufacturing difficulties in accommodating different inhaler devices and the unacceptable increase in cost of the device in an increasingly cost-conscious health care environment.